question Aluminium corrosion treatment?

[fv1609]

We are all familiar with rust treatments like Kurust etc. But is there any similarly easy thing that can be used on aluminium?

 

The most obvious places to be confronted with this problem are the steel/Permabright junctions on a Land Rover. The steel can be treated, but can the aluminium?

[Richard Farrant]

We are all familiar with rust treatments like Kurust etc. But is there any similarly easy thing that can be used on aluminium?

 

The most obvious places to be confronted with this problem are the steel/Permabright junctions on a Land Rover. The steel can be treated, but can the aluminium?

 

Clive,

 

Years ago, I used a treatment which was similar to Naval Jelly (for ferrous metals), it was specially for alloys, I used it on motor cycle parts. No idea of what it was called now though, it was a syrup or jelly consistence, brushed on, left for a time then washed off.

[fv1609]

Richard, the problem I'm finding is that although I can treat the rust, the aluminium damage of white flakiness is more extensive.

 

Even if I remove a steel bracket I can decide to treat it with Kurust or grind/polish it down to clean metal. Unfortunately if I attempt the same surgery on the aluminium, the damage will go much deeper before I can get into clean metal.

 

So let me know if you have a sleepless night & you suddenly remember what this stuff you used was called. I've done some gooogling but nothing of value turned up.

[radiomike7]

We are all familiar with rust treatments like Kurust etc. But is there any similarly easy thing that can be used on aluminium?

 

The most obvious places to be confronted with this problem are the steel/Permabright junctions on a Land Rover. The steel can be treated, but can the aluminium?

 

Clive, it is called Birmabright and is an NS4 type aluminium sheet. From memory it needs to be etch primed ASAP after rubbing down as it oxidises rapidly.

[fv1609]

Clive, it is called Birmabright and is an NS4 type aluminium sheet. From memory it needs to be etch primed ASAP after rubbing down as it oxidises rapidly.

 

Yes, as I understand it Birmabright is the aluminium alloy used used in the construction of a Land Rover. But having a replacement sheet wasn't what I was after, it was to neutralise corrosion in the Permabright.

[Richard Farrant]

So let me know if you have a sleepless night & you suddenly remember what this stuff you used was called. I've done some gooogling but nothing of value turned up.

 

Clive,

 

It was a phosphoric solution, I recollect that we used this in dipping tanks in the Workshops, for cleaning alloy engine parts, etc. I have found reference to a product called De-oxidine 200 being used on preserved aircraft fuselages where corrosion has taken place. as soon as it is treated, an etch primer suitable for alloys, should be used.

 

Just going back to sleep.........

[sirhc]

Clive,

 

You can use this stuff...

http://www.hammerite.com/uk/products/usage/ug_special_metals_primer.html

 

But you'll need to paint the parts, or did you want them to be silver?

 

Chris

[fv1609]

Clive,

 

It was a phosphoric solution, I recollect that we used this in dipping tanks in the Workshops, for cleaning alloy engine parts, etc. I have found reference to a product called De-oxidine 200 being used on preserved aircraft fuselages where corrosion has taken place. as soon as it is treated, an etch primer suitable for alloys, should be used.

 

Just going back to sleep.........

 

Ah I've just remembered I bought some automotive alunium cleaner to do the engine. You brush it on & then rinse thoroughly, but I suspect this is just to make superficially effected aluminium look better rather than a deep conversion.

 

Sleep? Oh no not yet you surely can't get to sleep without answering MO No.124?

[Richard Farrant]

 

Sleep? Oh no not yet you surely can't get to sleep without answering MO No.124?

 

 

If I wake up in the night with an idea of what MO 124 is, I will log back on...........................but I feel there is little chance of that.:-D

[fv1609]

Clive,

 

You can use this stuff...

http://www.hammerite.com/uk/products/usage/ug_special_metals_primer.html

 

But you'll need to paint the parts, or did you want them to be silver?

 

Chris

 

Chris but does that have any penetrative power? Obviously a good metal to paint adhesion will be of future benefit in keeping water & air out to prevent the electrolysis.

 

Obviously loose white stuff (aluminium oxide?) has to be removed. It was the compromised metal that remained that worried me, hoping for some stabilising chemical. Although I suppose if its really clean & still hard, one get good paint adhesion it won't progress.

[fv1609]

If I wake up in the night with an idea of what MO 124 is, I will log back on...........................but I feel there is little chance of that.:-D

 

Good grief man, you can't throw in the towel, no wonder we don't have an Empire any more! After all you have your reputation to maintain.

[alant]

Look on Light Aero Spares web site and you should find something to do the job.

Alan

[fv1609]

Look on Light Aero Spares web site and you should find something to do the job.

Alan

 

Ok Alan thank you for that. Several surface cleaners & preventive products there. I think this is the only treatment one. So it looks as if the attacked aluminium will scab off as it penentrates.

 

http://www.lasaero.com/site/products/article?id=L03GWAU6T

[paulob1]

considering what has happened in the oxidization of the alloy, i doubt you will find any metal left with which to treat...all that the rust removers do is either turn it into and inert barrier or etch out the rust..you can do that with the alloy by simple rubbing it down with a bit of solvol...not sure you can turn the oxidized alloy into anything without heating it...will ask a friend of mine who is a metallurgist...(for maclaren racing) just thought i would name drop there...

 

The biggerst issue for alloy and steel is the electolosis effect, you have to break the metal to alloy connection by fitting insulating rubber pieces...its essential as electrolosis will eat the alloy away in weeks...

[Adam Elsdon]

I had some of that phosphoric acid type stuff you add to water for the de-rusting of steel parts, what i did find is, used in a stronger mix, it just ate through aluminium oxide in no time at all, leaving the base metal, although if left on too long it starts eating that as well, the piece i tried it on was an aluminium alloy fan, that was heavily corroded, and it stripped all of the white powder corrosion clean off, i then primed it with Hammerites non ferrous metal primer, some of the pitting i filled with chemical metal.

 

If you are putting Birmabright/alloy back on to a steel frame, or if it is in contact with another metal, you can get a compound you paint on the surface before joining which prevents disimiliar metal corrosion, i have a tin of it somewhere, i will dig it out and find the name/supplier if you are interested.

[Richard Farrant]

The biggerst issue for alloy and steel is the electolosis effect, you have to break the metal to alloy connection by fitting insulating rubber pieces...its essential as electrolosis will eat the alloy away in weeks...

 

Not neccessary to use rubber as a barrier, it would be impractical in a lot of engineering circumstances. Take the case of CVR vehicles, where steel components are bolted to alloy hulls, a special marine coating is used as a barrier and works well from experience of it. It sticks like sh+t to a blanket, and unlikey to lift if sufaces are prepared.

[Adam Elsdon]

I think thats the stuff i have, its a strange greeny yellow colour if i remember correctly.

[fv1609]

My problem is the corrosion between pieces of frame & body. I can't get in underneath the interfaces properly without lifting the body & doing a major restoration. I'm bored fiddling around doing this anyway, I want to be working on the Pig & the Shorland, bless it, has very little Birmabright left on it.

[Adam Elsdon]

The stuff i have is called "Rylard marine finishes Duralac Jointing Compound" which inhibits electrolytic corrosion between dissimiliar metals.

 

The MOD Stock ref no on the stuff i have is 33/H2202110 although this was back in 1994!

[Adam Elsdon]

Richard, i dont suppose you know what "Aluminium cream" was used for? i have a couple of tins still sealed and wrapped in Poly as they were despatched from stores, it comes in two tins and is mixed in a two pack format, unfortunately i dont have them to hand for reference.

 

I should start a thread, "Tins of weird Mil spec goo, what was it used for"

 

I have a few tins which would fall under that banner!

[fv1609]

The MOD Stock ref no on the stuff i have is 33/H2202110 although this was back in 1994!

 

33H has the sound of a RAF DMC to it but I can't make any sense of the item by cross referencing to a NSN. Although Barium Chromate appears as Duralac by Lewelyn Ryland as NSN 6810-99-001-6288.

[Richard Farrant]

33H has the sound of a RAF DMC to it but I can't make any sense of the item by cross referencing to a NSN. Although Barium Chromate appears as Duralac by Lewelyn Ryland as NSN 6810-99-001-6288.

 

The coating we used, came through the NSN system and was a International Marine product, colour looked like zinc chromate primer, a sickly yellow.

[Adam Elsdon]

Clive, most of the miscellaneous tins of goo i have knocking around the shed were from RAF lossiemouth, which would explain the RAF DMC numbering.

Once it had expired it was disposed of, although i have had a number of tins of paint long past it alleged expiry, which have been absolutely fine, although that probably isnt always the case i suspect.

[fv1609]

I should start a thread, "Tins of weird Mil spec goo, what was it used for"

 

Come to think of it, there was a similar thread about corrosion on CVR bodies about 6 months ago & I think at least 3 types of products were identified.

[griff66]

in the aviation industry there is stuff called alodine and aliprep puts a protective coating on ali, if u found corrosion grind it off treat area and spray paint zinc chromate v good, nasty stuff though!

[malyutkaman]

I agree with "griff66" what you need to treat alluminum is a conversion coating such as allodine. It penetrates the surface and helps the metal resist corrosion. Also when joining dissimilar metals (alluminum and steel) the greenish yellow pasty stuff is called "Mastinox", it is a zinc chromate paste that acts as a barrier between the two metals. Using both of these products should do the trick.